It’s springtime for businesses that depend on advertising — especially the Internet and cable TV — according to a new forecast from media services firm ZenithOptimedia. With the economy “in a much better place than it was two years ago,” it says U.S. spending will rise 3.6% this year to $159.7B, and will keep growing by 3.8% next year and 4.8% in 2014. Network TV won’t join the fun: Its sales are expected to be -1% to $17.9B this year,  -2.5% in 2013, and -3% in 2014. Even though this year will be helped by the London Olympics, the time difference with the U.S. “will mean fewer events airing live than there were (in 2010) for the Vancouver Olympics,” ZenithOptimedia says. Cable’s a different story, with overall sales expected at +10% to $20.1B this year, then rising +10.5% and +11%. General audience services including USA Network, TBS, and FX are increasingly seen as alternatives to broadcast networks and will build momentum “largely thanks to the return of big-spending automotive and financial advertisers.” The forecasters say they expect to see local spot sales +8% this year to $21.7B (then +2.0% and +4.0%) while syndication is -12% to $2.2B in 2012 (then -10.5% and -11%).

In other media, the Internet will soar to second place — behind all television — with sales +17.8% to $30.6B (then 18.7% for each of the following two years). Newspapers will slide to No. 3 with ads -8% to a little under $25B, and declining at the same pace the following two years. Radio will pick up 3% to $16.7B, but will ease to +2% and +1%. Consumer magazines will be -3% to $14.6B this year, then -3% and -2%. And outdoor ads will come in +4.2% to $7.6B, then +5% the next two years. And movie theater advertising pulls up the rear, +5% to $725M, continuing the +5% pace for 2013 and 2014.